xxxiv REPORT — 1865. 



and in this room the preliminary observations were made for determining the 

 constants of the two pendulums about to be used in India. These observa- 

 tions were made by Mr. Loewy, and the results have been communicated to 

 the Eoyal Society by the Superintendent, in conjunction with the observer. 

 The pendulums and other apparatus were subsequently taken to India by 

 Mr. J. Hennessey, and have arrived safely at the head quarters of the Trigo- 

 nometrical Survey. 



General Sabine has been informed by Mr. Meldrum, Director of the 

 Mauritius Observatory, that the necessary funds have been .-voted by the 

 Government of that colony for hourly meteorological and magnetical observa- 

 tions; and that he may shortly be expected in this country, in order to become 

 acquainted with the working of the Kew instruments. In consequence of 

 this communication, Mr. Adie has constructed a set of self-recording mag- 

 netographs, in readiness for Mr. Meldrum's arrival. 



A Dip Circle and Unifilar have been verified at Kew, and will shortly be 

 dispatched to Mr. Ellery, Director of the Observatory, Melbourne, Australia. 



Two Dip Circles and two Unifilars, ordered by Colonel Walker, R.E., Super- 

 intendent of the Indian Survey, have been Verified in the presence of Colonel 

 Walker, who has received instruction in the method of observation with these 

 instruments. They have since been sent to India, where they have safely 

 arrived. 



Three Dip Circles and three Unifilars, ordered by Colonel Strange, are being 

 verified at the Observatory, and likewise one Dip Circle and one Unifilar re- 

 cently ordered by Captain J. Belavenetz of the Russian Navy, for the Compass 

 Observatory just built at Cronstadt. 



Mr. E. Walker (who has received the Cambridge Adams prize for his 

 essay on terrestrial magnetism) has been at Kew Observatory, receiving 

 instruction in the use of magnetical instruments. 



The usual monthly absolute determinations of the magnetic elements con- 

 tinue to be made ; and the self-recording magnetographs are in constant 

 operation, as heretofore, under Mr. Whipple, magnetical assistant, who has 

 displayed much care and assiduity in the discharge of his duties. 



The meteorological work of the Observatory continues to be performed by 

 Mr. Thomas Baker, who likewise takes charge of the photographic depart- 

 ment connected with the self-recording instruments, and executes both 

 offices very satisfactorily. 



Since the Meeting at Bath, Senhor da Souza, of the University of Coimbra, 

 has ordered a self-recording barograph and thermograph, an anemometer and 

 electrograph, tubes for filling by Mr. Welsh's process in order to obtain a 

 standard barometer, and a cathetometer. These instruments have been con- 

 structed by opticians, and forwarded to Coimbra. 



During the past year, 88 barometers and 420 thermometers have been veri- 

 fied, and 6 standard thermometers have been supplied to men of science 

 and opticians ; 3 sets of measures of capacity have likewise been verified. 



The Self-recording Barograph continues in constant operation, and traces 

 in duplicate are obtained, one set of which has been regularly forwarded to 

 the meteorological department of the Board of Trade. 



At the request of Mr. Charles Cator, an anemometer of his construction 

 has been tested at the Observatory, and the restdts communicated to him. 

 Also, at the request of Professor Roscoe, the photographic action of total 

 daylight is daily registered by an apparatus of his construction. 



The Kew Heliograph, in charge of Mr. De la Rue, continues to be worked 

 by a qualified assistant, who gives much satisfaction. During the past 

 year 243 negatives have been takeif on 146 days, and four sets of positives 



